Where to find an unwanted hamster?

Not sure. Have you tried putting up an ad on these sites? Usually reputable breeders avoid classifieds bc they don't want the negative attention from someone wanting a Cute Hamster. Try the vets who specialise in exotics, maybe they have a contact.

Also, try the shelters. Even regular shelters are somtimes burdened with small animals. If you have a small animal rescue contact them, if not contact someone with the regular shelter. Ours in town takes small animals before having them driven to in-town or out-of town fosters for the rescue. These organizations are usually inter-linked Good luck!

Like Purple-Hops said, I'd try contacting any local shelters/rescues in your area. Especially if you have any small animal/exotic rescues. I know one of my local rabbit rescues commonly also has other small animals like hamsters, rats, degus, etc.

They may not advertise small animals like rodents for adoption as much as they do larger animals. Especially if their main focus is with another type of animal.

Plus if you talk to them, even if they don't currently have any hamsters, most shelters/rescues would be more than happy to keep your contact information and contact you when/if they do have any animals they think you might like surrendered.

I have tried the local rescues and shelters, none of them seem to ever have hamsters I'll maybe ask some to keep me updated though.

I'm not actually looking for a hamster bred by a reputable breeder or anything, more just a hamster who isn't getting any attention because it's unwanted.

I've only had time to put an add up on Preloved so far, I'm going to put them up on other sites too though

Okay so I posted "wanted" adverts to:

Preloved
Gumtree
Adflyer
UKPetMart
Oodle
Craigslist

Any other suggestions? Are there any forums where I can post ads?

Ah, I found some! http://www.preloved.co.uk/fuseaction-adverts.showadvert/index-1034589349/137b8429.html

Just up yesterday, two girls free with cage and accessories about an hour away from me I can't respond to the advert yet though, because I'm not a full member Hopefully they don't go quickly.

I'm glad you found a good resource. I use craigslist to find pets in need of homes.